/*
 * Copyright 2002-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jdbc.core.metadata;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.dao.DataAccessResourceFailureException;
import org.springframework.jdbc.support.DatabaseMetaDataCallback;
import org.springframework.jdbc.support.JdbcUtils;
import org.springframework.jdbc.support.MetaDataAccessException;
import org.springframework.jdbc.support.nativejdbc.NativeJdbcExtractor;

import javax.sql.DataSource;
import java.sql.DatabaseMetaData;
import java.sql.SQLException;

/**
 * Factory used to create a {@link TableMetaDataProvider} implementation based on the type of databse being used.
 *
 * @author Thomas Risberg
 * @since 2.5
 */
public class TableMetaDataProviderFactory {

    private static final Log logger = LogFactory.getLog(TableMetaDataProviderFactory.class);


    /**
     * Create a TableMetaDataProvider based on the database metedata
     *
     * @param dataSource used to retrieve metedata
     * @param context    the class that holds configuration and metedata
     * @return instance of the TableMetaDataProvider implementation to be used
     */
    public static TableMetaDataProvider createMetaDataProvider(DataSource dataSource, TableMetaDataContext context) {
        return createMetaDataProvider(dataSource, context, null);
    }

    /**
     * Create a TableMetaDataProvider based on the database metedata
     *
     * @param dataSource          used to retrieve metedata
     * @param context             the class that holds configuration and metedata
     * @param nativeJdbcExtractor the NativeJdbcExtractor to be used
     * @return instance of the TableMetaDataProvider implementation to be used
     */
    public static TableMetaDataProvider createMetaDataProvider(DataSource dataSource,
                                                               final TableMetaDataContext context, final NativeJdbcExtractor nativeJdbcExtractor) {
        try {
            return (TableMetaDataProvider) JdbcUtils.extractDatabaseMetaData(dataSource,
                    new DatabaseMetaDataCallback() {
                        public Object processMetaData(DatabaseMetaData databaseMetaData) throws SQLException {
                            String databaseProductName =
                                    JdbcUtils.commonDatabaseName(databaseMetaData.getDatabaseProductName());
                            boolean accessTableColumnMetaData = context.isAccessTableColumnMetaData();
                            TableMetaDataProvider provider;
                            if ("Oracle".equals(databaseProductName)) {
                                provider = new OracleTableMetaDataProvider(databaseMetaData,
                                        context.isOverrideIncludeSynonymsDefault());
                            } else if ("HSQL Database Engine".equals(databaseProductName)) {
                                provider = new HsqlTableMetaDataProvider(databaseMetaData);
                            } else if ("PostgreSQL".equals(databaseProductName)) {
                                provider = new PostgresTableMetaDataProvider(databaseMetaData);
                            } else if ("Apache Derby".equals(databaseProductName)) {
                                provider = new DerbyTableMetaDataProvider(databaseMetaData);
                            } else {
                                provider = new GenericTableMetaDataProvider(databaseMetaData);
                            }
                            if (nativeJdbcExtractor != null) {
                                provider.setNativeJdbcExtractor(nativeJdbcExtractor);
                            }
                            if (logger.isDebugEnabled()) {
                                logger.debug("Using " + provider.getClass().getSimpleName());
                            }
                            provider.initializeWithMetaData(databaseMetaData);
                            if (accessTableColumnMetaData) {
                                provider.initializeWithTableColumnMetaData(databaseMetaData, context.getCatalogName(),
                                        context.getSchemaName(), context.getTableName());
                            }
                            return provider;
                        }
                    });
        } catch (MetaDataAccessException ex) {
            throw new DataAccessResourceFailureException("Error retrieving database metadata", ex);
        }
    }

}
